Diagrammatic rhymes with:
epigrammatic, epigrammatic, programmatic, aromatic, dramatic, epigrammatic, melodramatic, programmatic, aromatic, asymptomatic, automatic, axiomatic, cinematic, diplomatic, dramatic, emblematic, epigrammatic, idiomatic, mathematic, melodramatic, problematic, programmatic, psychosomatic, semiautomatic, symptomatic, systematic, telematic, undiplomatic